Ensure that parallel version of builtin functions produce the
same results as the serialized version of the function:

for == pfor == pforn
map == pmap == pmapn
filter == pfiltern
part == ppart == ppartn
where == pwheren
Merge pull request #19 from brbaker/parallel.tests

Test that parallel and serial functions produce the same result
1. added vectorizing modifiers for intix ops. These desugar to
builtin combinators eachleft, eachright, which vectorize left
and right arguments, respectively. I.e.
[0, 1, 2] ~+ 10 == 10 +~ [0, 1, 2] == [10, 11, 12]. Only docs
at present are the relevant additions in MeshParser.rats, misc.m
and test_intrinsics.m, unfortunately.

2. Added other library functions: constrain, cutpoints, fruntot,
runtot, starts, trace, tracen. Renamed old trace to tconverge.
Added tests and docs for these.

3. Removed library functions countn, rangen, fromton.

4. Fixed bugs in chunks, pwheren.
Merge branch 'master' of https://github.com/bhosmer/mesh into bhosmer-master